In general, in a silver halide photographic light-sensitive material, the incorporation of light absorbing compounds into a silver halide emulsion layer or other hydrophilic colloid layers has been carried out in order to absorb a light of a specific wavelength in order to achieve sensitivity adjustment, improvement in safety of safelight, color temperature adjustment of light, prevention of halation, and adjustment of sensitivity balance in a multilayered color light-sensitive material.
For example, when a silver halide photographic light-sensitive material, which comprises a support and hydrophilic colloid layers such as a light-sensitive silver halide emulsion layer, is subjected to imagewise exposure in order to record an image on the light-sensitive silver halide emulsion layer, it is necessary to control the spectral composition of light incident to the silver halide emulsion layers in order to improve photographic sensitivity. In this instance, usually a method is employed in which a dye, which is capable of absorbing light of a wavelength unnecessary for the above silver halide emulsion layer, is incorporated into the hydrophilic colloid layers farther from the support than the above light-sensitive silver halide emulsion layer to form a filter layer and only light of a desired wavelength is transmitted.
For the purpose of improving image sharpness, an anti-halation layer is provided between a light-sensitive layer and a support or on the backside of the support to absorb harmful reflected light at the interface between the emulsion layer and support or on the backside of the support.
Further, a dye capable of absorbing light of a wavelength region in which silver halide is sensitive is used on some occasions for a silver halide emulsion layer for the purpose of preventing irradiation in order to improve the sharpness of an image.
Particularly, a silver halide photographic light-sensitive material used for a plate making process, more specifically a light-sensitive material used in a light room, contains a dye absorbing UV rays and visible rays in a light-sensitive layer or a layer present between the light source and light-sensitive layer in order to increase the safety against the safe-light.
Further, in an X-ray sensitive material, a coloring layer is provided on some occasions to improve sharpness, which serves as a crossover cutting filter for decreasing crossover rays.
These coloring layers consist of hydrophilic colloid in many cases and, therefore, a dye is usually incorporated into the layers for coloring. The inventor sought dyes having the following characteristics:
(1) an appropriate spectral absorption according to its uses and purposes;
(2) photochemical inactivity, i.e., not exerting negative chemical effects on a silver halide photographic layer, e.g., lowering of sensitivity, degradation of the latent image, and fogging;
(3) an ability to be bleached, dissolved and removed in photographic processing steps without leaving harmful color on the processed photographic light-sensitive material; and
(4) an excellent aging stability in a coating liquid (solution) or a silver halide photographic material without a change in quality.
Many efforts have been made in order to discover dyes satisfying these conditions.
Where the layers containing the dyes function as a filter layer and an anti-halation layer, it is preferred that the layers concerned are selectively colored and the other layers are not substantially colored, because if the other layers also are substantially colored, not only is a harmful spectral effect exerted but also the effectiveness as a filter layer and an anti-halation layer are reduced.
Many means have been investigated, and it has been proposed to fix a dye in a specific layer in a photographic light-sensitive material by incorporating the dyes in a dispersed solid form, as disclosed in JP-A-56-12639 (the term "JP-A" as used herein means an unexamined published Japanese patent application}, JP-A-55-155350, JP-A-55-155351, JP-A-52-92716, JP-A-63-197943, JP-A-63-27838, and JP-A-64-40827, EP-B-15601 and EP-A-276566, and WO88/04794.
In the above publications, the dyes are generally dispersed in solid form (a dye solid particle dispersion) with anionic surface active agents (a wetting agent), e.g., sodium oleyl methyltauride is disclosed as a dispersant in JP-A-52-92716 and Triton X200.RTM. is disclosed as a dispersant in W088/04794.
However, where the dyes are dispersed in solid form as described above, the stability of the dispersion is deteriorated depending on the dispersants selected which immediately cause settling and flocculating, and when the dyes are mixed with a hydrophilic colloid, they flocculate to form a lump or the apparent absorbance is lowered. Further, the particle size of the dye dispersed in a solid form does not become small and the broadening of the absorption spectrum in the coated layer takes place.
Accordingly, the selection of a dispersant which has an improved dispersing property and which has less of a negative effect against photographic properties was sought by the inventor who has now found the preferable combination of a dye and a dispersant.